Antonov Alexander

Optigraph Gmbh

Highly annealed pyrolytic graphite (HAPG) is an advanced type of pyrolytic graphite that, as a mosaic crystal, combines high integral reflectivity with a very low mosaicity of typically less than 0.1°. When used as dispersive X-ray optics, a high resolving power has been observed, rendering HAPG very suitable for applications in high-resolution X-r...

X-ray optics with high energy resolution and collection efficiency are required in X-ray spectroscopy for investigations of chemistry and coordination. This is particularly the case if the X-ray source emits a rather weak signal into a large solid angle. In the present work the performance of a spectrometer based on thin mosaic crystals was investi...

X-Ray Fluorescence analysis (XRF) is a reliable multi-elemental and nondestructive analytical method widely used in research and industrial applications. This practical handbook provides self-contained modules featuring XRF instrumentation, quantification methods, and most of the current applications. The broad spectrum of topics is due to the effo...

The use of flat and bent highly oriented pyrolytic graphite (HOPG) crystals as X-ray monochromators in X-ray fluorescence analysis.

Results of the investigation of a short-focus parabolic concentrator from pyrograhite are presented. The focus size (FWHM) of the concentrator is 3.6 mm in the focal plane and 6.9 mm along its axis. The neutron intensity in the focus is up to 10 times more than in the primary beam. The angle aperture of the device is about 53°. Possible application...

Highly Oriented Pyrolytic Graphite (HOPG) is a mosaic crystal, which consists of a large number of small nearly perfect crystallites. The unique structure of HOPG crystals enables them to be highly efficient in diffraction in an energy range between 2 keV up to several 10 keV. The mosaicity of the crystal is responsible for the dramatic increase of...

Highly Oriented Pyrolytic Graphite (HOPG) is a mosaic crystal, which consists of a large number of small nearly perfect crystallites. The unique structure of HOPG crystals enables them to be highly efficient in diffraction in an energy range between 2 keV up to several 10 keV. The mo-saicity of the crystal is responsible for the dramatic increase o...

By the use of a thin highly oriented pyrolytic graphite crystal (HOPG) bent to a high-performance ellipsoidal shape it was possible to focus monochromatic x-rays of 4.5 keV photon energy with an efficiency of 0.0033, which is 30 times larger than for previously used bent crystals. Isotropic Ti K alpha radiation of a 150 microm source was focused on...

A new method of producing strongly bent highly oriented pyrolytic graphite (HOPG) is presented. The method allows one to make a crystal of almost arbitrary shape, but has some thickness limits. A review of the results obtained on this type of crystal by different laboratories during the last 10 years is given. An x-ray intensity gain from a synchro...

Semitransparent HOPG monochromators are being investigated with an emphasis on their potential applications in X-ray imaging systems. HOPG plates and films, 5-100micrometers thick and up to 14 cm2 in area, were tested. Scanning techniques were used to measure the profiles of local reflectivity and transparency at different monochromator thicknesses...

Recently, it has been demonstrated that an x-ray detector in the form of a log spiral of revolution, covered with highly oriented pyrolytic graphite, is an excellent device for obtaining the fluorescence XAFS of an element of interest in the presence of competing fluorescence from other elements. In the present work we investigate the capabilities...

The use of bent crystals with high integrated reflectivity in focusing crystal spectrometers (Johann and von Hamos schemes) is considered. It is shown that in a von Hamos scheme mosaic focusing takes place. Thus a mosaic crystal simultaneously provides high spectral resolution and high efficiency. Expressions for the mosaic focusing are obtained. F...

We have constructed an x-ray monochromator based on a log spiral of revolution covered with highly oriented pyrolytic graphite. Such a monochromator is used for obtaining x-ray absorption edge fine structure by the fluorescence method, and is particularly useful for measuring the fine structure of dilute element A in a concentrated matrix of elemen...

Results of the experimental testing of the focusing parabolic pyrolytic graphite X-ray monochromator on the wiggler synchrotron radiation beamline of the VEPP-3 storage ring (2 GeV, 100–150 mA) are presented. The monochromatization and the focusing of X-radiation in both vertical and horizontal directions are provided by the optical properties of t...

Results of the experimental testing of the focusing parabolic pyrolytic graphite X-ray monochromator on the wiggler synchrotron radiation beamline of the VEPP-3 storage ring (2 GeV, 100-150 mA) are presented. The monochromatization and the focusing of X-radiation in both vertical and horizontal directions are provided by the optical properties of t...

The results of the experimental testing of the parabolic focusing pyrolytic graphite x‐ray monochromator (mono) on the wiggler (2 T) synchrotron radiation (SR) beamline of the VEPP‐3 storage ring are presented. The monochromatization and the focusing of x radiation in both vertical and horizontal directions are provided by the optical properties of...

A series of focusing monochromators made from shaped pyrolytic graphite with 240 to 5 mm radii of curvature was developed and tested using SR beams. Using the same technology, cylindrical dispersion filters for secondary monochromatization during XFA were manufactured. The first results of the XFA tests of X-ray optical elements from shaped pyrogra...

A set of highly bent crystal monochromators made from formed pyrolytic graphite has been tested using synchrotron-radiation beams from the storage ring VEPP-3. These crystals were used in the following devices: short-focus wide-band monochromator and cylindrical dispersion filter of secondary (fluorescent) radiation.

The grain-size composition, specific surface, and structural features of a powder of heat-treated pyrographite ground in a disintegrator-activator have been studied. A comparison has been made with powders ground by other methods (abrasion, ball mill).

The laws in the change in the specific surface of disperse carbonaceous materials determined by the air filtration method and by the adsorption of liquid nitrogen are considered. The existence of linear relationships between them in the ranges of the parameters investigated has been shown. An optimum on the curve of the dependence of the amount of...

An x-ray focusing crystal von Hamos spectrometer was developed using mica and graphite cylindrical crystals (radius of curvature R=20 mm) with a CCD linear array detector. The commercial CCD (Toshiba model TCD 1304AP) used for x-ray detection has 3724 pixels (8 μm width and 200 μm height) giving a total length of ~30 mm. The CCD detector was absolu...